How can I count / view all fast-path sockets on windows server?

Question

In case you're not familiar, fast path loopback sockets:

https://blogs.technet.microsoft.com/wincat/2012/12/05/fast-tcp-loopback-performance-and-low-latency-with-windows-server-2012-tcp-loopback-fast-path/

How can I count how many connections of this type a system currently have?

Thanks!

score 0 · Accepted Answer · answered Jul 03 '18 at 11:40

Answering self for future seekers (partial answer though):

There's no way to count it on windows (at least from what I found), but you can count sockets that user requested to be fast-path but windows rejected and used plain loopback instead. So if you know how many fast-path sockets were supposed to be opened, you can use that counter to see if any of them failed.

To access that counter open perfmon.exe and add the following counter:

TCPIP Performance Diagnostics/TCP connect requests fallen off loopback fast path

Leaving the question opened for now in case someone have a better answer.

How can I count / view all fast-path sockets on windows server?

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